1. Field of the Invention
The present invention relates to a structure of support of a focusing head of a laser beam of a machine for working metal or non-metal parts.
2. Related Art and Other Considerations
Machines are known that use a laser beam for performing workings of metal parts, such as metal sheets, or non-metal parts. Typical workings are shearing, welding and the like. The laser beam is generated by a source of laser radiations and directed toward a focusing head along an optical path wherein there are elements of deviation of the beam, e.g., mirrors and a focusing lens.
In order to perform the workings, it is necessary to make a relative movement between the laser beam (emitted by the focusing head in a direction orthogonal to a surface of the part) and the part to be worked (resting on a substantially rectangular working plane). The relative movement can be obtained with the movement of the piece (fixed optics), with the combined movement of the laser beam in one direction and of the part in another direction (mixed optics) or, lastly, with the movement of the laser beam only (mobile optics).
In machines with mobile optics a first requirement is a high mechanical stability of the structures of support of the elements of deviation of the laser beam (mirrors) present along the optical path.
Thus, the embodiment most frequently adopted is the so-called portal one wherein a girder structure is slidably supported at the ends on two parallel pathways obtained in two portals situated on two long sides of the machine. In addition, a carriage, that houses the focusing head, is driven to move along the girder, in a direction orthogonal to the pathways, that is in a direction parallel to two short sides of the machine.
This solution has the disadvantage of limiting accessibility to the working plane along the long sides of the machine penalising in such a way the steps of adjustment, maintenance and operation.
Another known embodiment is the so-called cantilever one, wherein a structure with a projecting (cantilever) girder is mobile along just one pathway obtained in a shoulder situated along one long side of the machine. In this case again, the carriage, that houses the focusing head, is driven to move along the girder, in a direction orthogonal to the pathway of the girder. The cantilever embodiment improves accessibility to the working plane because it leaves free three sides of the machine. However, it does force a limitation of the dynamic performances of the movement of the cantilever girder and/or of the stroke of the carriage along the girder. Or, again, it forces the adoption of complex mechanical solutions in order to compensate for the deflections and torsions that the cantilever girder inevitably involves.
The object of the present invention is a structure of support of a focusing head of a laser beam that has a high structural stability, great accuracy in the movement and a high degree of accessibility to the working plane.